Subject: Re: [stella] I can't find it From: "Andrew Davie" <adavie@xxxxxxxxxxxxx> Date: Tue, 12 Sep 2000 14:30:47 +1000 
Hi everyone I wrote to George Woltman regarding this  George is the head honcho in charge of GIMPS  the great internet mersenne prime search (www.entropia.com/primenet). Mersenne primes are of the form (2^p)  1, and they are dealing with milliondecimaldigit primes these days. I run Prime95, a distributed prime checker, on my PC eating up idle cycles  and have done so for a number of years, now. I was hoping the system/program could be used to crack our number. George was kind enough to respond, but unfortunately quenched my hope. I copy his email verbatim... we need a different approach :) Cheers A Hi, You won't be able to factor it. The best known factoring algorithm at present is the Number Field Sieve (NFS). Using current computers it can crack numbers up to roughly 200 digits. That's using a distributed approach to run the sieve and a supercomputer to run the final step. The suggestion of factoring it by brute force by dividing up the key space would take eons. The poster that thought he would get a list of known large primes doesn't understand how this number was constructed. It is not done using a list of known 130 digit primes. My PC can find 2 130 digit primes in less than a second. Hope that helps, George At 01:56 PM 9/12/00 +1000, you wrote: >However, a recent discussion on the [stella] mailing list (devoted to >modernday programmers of the video game systems from the mid 1970s  in >particular, the Atari 2600) about the copy protection on an Atari machine >which uses a rather large decimal number which needs to be factorised, >prompts me to write. >You can see the number and some discussion in the email copied, below. >I'm wondering, is it possible to factorise this number using Prime95? A >long shot, I suppose, but I'm thinking that prime95 is dealing with numbers >many magnitudes larger than this already. By factorising this number, many >homebrew programmers would be able to produce new games/programs for this >longdead console. >Thanks for any help/advice you might be able to provide. >Hope this finds you well. >Cheers >A > >Andrew Davie adavie@xxxxxxxxxxxxx & adavie@xxxxxxxxxxxxxxxxx ICQ #3297382 >Museum of Soviet Calculators @ www.taswegian.com/MOSCOW/soviet.html >FAQ @ www.taswegian.com/TwoHeaded/faq.html Work @ www.bde3d.com > > > Original Message  >From: "Russ Perry Jr" <slapdash@xxxxxxxxxxxx> >To: <stella@xxxxxxxxxxx> >Sent: Tuesday, September 12, 2000 12:13 PM >Subject: RE: [stella] I can't find it > > > > Do we know anything else about this number? It's the product of two > > large primes, right? Or possibly more than that?? > > > > I remember looking one other time for a list of large primes without > > much success. But I guess if such lists existed, this sort of problem > > wouldn't be very insteresting, would it? And determining primes isn't > > exactly a quick science either from what I understand. > > > > Heh, it's not divisible by 2 or 3... And the last digits would be 1 & 3 > > or 7 & 9 if only two multiplicands. That should narrow it down enough > > for you guys. :) > > > > More seriously, perhaps a distributed computing effort like the RSA/DES > > challenges or SETI would work? Break the keyspace up into all numbers > > between 1 and that whole thing that end in 1 & 3 or 7 & 9, and let people > > try multiplying all those numbers until SOMEONE finds it. Might be a > > nice RGVC project, assuming the keyspace splitter and calculator server > > & client aren't too hard to program... > > > > John Saeger wrote: > > >Here's the number that we'd like to factor: > > > > > > >372763642186038806257268716646134295445276919770501371632454989813933011717 >1 > > > >918154782270776663547170932295686631340166371502363305352251508921925382211 >5 > > > >983319169296763298520553286632782878137984247708495679525591638977292185426 >5 > > >394451056360909015523895044054544800868529030160209747657273 > > > > John K. Harvey wrote: > > >> I've browsed the stella archives, and can't find the big base10 > > >> respresentation of the 7800 encryption number that can't be broken. >Can > > >> anyone help me find it? > >  > > //*================================================================++ > >  Russ Perry Jr 2175 S Tonne Dr #105 Arlington Hts IL 60005  > >  8479529729 slapdash@xxxxxxxxxxxx VIDEOGAME COLLECTOR!  > > ++================================================================*// > > > >  > > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > > Unsub & more at http://www.biglist.com/lists/stella/ > >  Andrew Davie adavie@xxxxxxxxxxxxx & adavie@xxxxxxxxxxxxxxxxx ICQ #3297382 Museum of Soviet Calculators @ www.taswegian.com/MOSCOW/soviet.html FAQ @ www.taswegian.com/TwoHeaded/faq.html Work @ www.bde3d.com  Original Message  From: "Rob" <kudla@xxxxxxxxx> To: <stella@xxxxxxxxxxx> Cc: <stella@xxxxxxxxxxx> Sent: Tuesday, September 12, 2000 12:52 PM Subject: RE: [stella] I can't find it > At 09:13 PM 9/11/00 0500, Russ Perry Jr wrote: > >More seriously, perhaps a distributed computing effort like the RSA/DES > >challenges or SETI would work? Break the keyspace up into all numbers > > Well, it took a distributed team a couple weeks last year to crack a > 128bit key, so if we got the same size team together, it would only take > 2^(960128) weeks to crack this one.... right? > > Rob > > kudla@xxxxxxxxx ... http://kudla.org/raindog ... Rob > > >  > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > Unsub & more at http://www.biglist.com/lists/stella/ >  Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
Current Thread 


< Previous  Index  Next > 

RE: [stella] I can't find it, Rob  Thread  Re: [stella] I can't find it, Russ Perry Jr 
RE: [stella] I can't find it, Joe Grand  Date  RE: [stella] I can't find it, Russ Perry Jr 
Month 